Thermal shock behavior of ZrB₂-based sharp leading edges evaluated by a novel water spraying method

Reliable evaluation of the thermal shock behavior of complex-shaped components is very important for ultra-high temperature ceramics. Unfortunately progress in this field is hampered by a lack of available experimental methods. Here, a novel water spraying method is proposed to investigate the thermal shock behavior of ZrB₂-based sharp leading edges (SLEs). Results indicated that the introduction of graphite flakes significantly improved the thermal shock resistance of ZrB₂-SiC (ZS) SLEs. However, owing to the anisotropies of microstructure and thermal conductivity of ZrB₂-SiC-G (ZSG) ceramic, the thermal shock resistance and the failure mode of ZSG SLEs were sensitive to the sampling orientation, which also were remarkably influenced by the size and/or shape of SLEs, leading to the variability of critical failure temperature from 750 °C to 375 °C and crack patterns from deflection to wave-shaped.